multiple controller question

I have been looking through a bunch of forums the last couple days looking for ways to get my controllers to work with project 64. I have a mayflash with 3 ports: ps2. N64, and SS. I have the controllers all working but when I want to play 2 players like mario kart 64 for example even though they have different buttons, when I start to accelerate with controller 1 player 2 moves at the sametime. So what I really want to know is can I use 1 adator with different ports to play multi player games or will I have to go out and buy another one?

Does Windows perceive the device as one controller or multiple controllers? (In the Windows Control Panel, under Gaming Devices (or Game Controllers) is there more than one entry for the adapter?) If the adapter only presents a single controller to the OS, you'll need one for each controller.